The present invention relates, generally, to a moveable antenna for use with a cellular telephone, radio, or other communication device, and more particularly to an antenna employing a hybrid radio frequency (RF) and direct current (DC) circuit for transmitting RF signals to and from its associated communication device.
Portable communication devices, such as cellular telephones, two-way and multi-party radio communication devices, and the like often employ a retractable and sometimes even a removable antenna assembly. To achieve optimum performance, it is advisable to orient the antenna vertically, particularly when receiving radio frequency (RF) transmission which is vertically oriented. However, communication devices (e.g., cellular telephones) having antennas which are not rotatable often suffer impaired transmission performance if the antennas are not oriented vertically during normal use of the cellular phone.
Other known cellular telephones employ antennas which are removable. Typically, these phones continue to transmit an RF signal even when the antenna is removed. This can result in unnecessary power depletion and unnecessary wear on the electrical components which make up the transmission circuit.
Existing cellular telephones which employ a moveable antenna utilize a dedicated RF circuit for transmitting and receiving RF signals, as well as a dedicated DC circuit for carrying a signal to the telephone host processor which indicates antenna orientation and whether the antenna is connected or removed. The use of such a dedicated RF circuit and a dedicated DC circuit results in increased manufacturing costs and reduces reliability and performance.
A positionable antenna assembly for use with portable communication devices is thus needed which overcomes the shortcomings of the prior art.